Lithium battery pack

Abstract

For a lithium battery pack including battery cells the number of which is larger than the number of battery cells 111 that can be monitored by a voltage detect portion 115, there is disposed a temperature detect element 113 for detecting the temperatures of the battery cell 112 not monitored by the voltage detect portion 115, and, when the temperatures of the battery cell 112 detected by the temperature detect element 113 rise beyond a given value, there is issued a signal to stop the charging of the battery pack.

1. A lithium battery pack comprising:
 at least five lithium battery cells; 
 a protection IC including four voltage detect portions that are connected to four lithium battery cells, respectively, the four voltage detect portions for detecting the respective voltages of four lithium battery cells; 
 a temperature detect element for detecting temperature of a lithium battery cell that can not be monitored by the four voltage detect portions, 
 wherein the number of the plurality lithium battery cells is larger than the number of lithium battery cells that can be monitored by the voltage detect portion, and 
 wherein if the temperature of the battery cell detected by the temperature detect element is equal to or higher than a given value, charging to the at least five lithium battery cells is stopped. 
 
     
     
       2. The lithium battery pack according to  claim 1 , further comprising:
 a switching element being connected in series to the lithium battery cells,
 wherein the switching element cuts off a connection to the lithium battery cells when the voltages of the lithium battery cells detected by the voltage detect portion are out of a predetermined range.